How can you tell if a value is not numeric in Oracle?

Question

I have the following code that returns an error message if my value is invalid. I would like to give the same error message if the value given is not numeric.

Answer 1

From Oracle DB 12c Release 2 you could use VALIDATE_CONVERSION function:

VALIDATE_CONVERSION determines whether expr can be converted to the specified data type. If expr can be successfully converted, then this function returns 1; otherwise, this function returns 0. If expr evaluates to null, then this function returns 1. If an error occurs while evaluating expr, then this function returns the error.

 IF (VALIDATE_CONVERSION(value AS NUMBER) = 1) THEN
     ...
 END IF;

db<>fiddle demo